Immunogen's T-DM1 Gets Presidential Treatment

| About: ImmunoGen, Inc. (IMGN)

Immunogen (NASDAQ:IMGN) is still trying to recuperate from the controversial rejection of T-DM1's accelerated approval filing. The message Immunogen was trying to convey is that nothing has changed in terms of T-DM1's long term potential. According to the company, the FDA's problem was not with the drug's stellar activity but the patient population enrolled on the trial. In just over a week from now, it could have the data to prove it.

Although the next potential filing is expected only in 2012 based on an ongoing phase III trial (EMILA study), T-DM1 will have two important data read-outs at next month's ESMO conference. The first is a phase II study where it is compared to chemotherapy+ Herceptin, the current standard of care for 1st line breast cancer patients. As I reviewed last month, expectations from this trial are high given Roche's (OTCQX:RHHBY) decision to start a pivotal trial based on a similar trial design.

Now investors have another reason for optimism: T-DM1's 1st line data is included in the presidential symposium, to be held on October 11th. Organizers typically put the most interesting presentations in this kind of sessions, so it safe to assume the trial is not a total flop. Just to give a sense of the profile of this session, other presentations in the presidential symposium include Cougar's phase III in prostate cancer and a phase III study of Avastin in ovarian cancer. Both studies have already been touted as successful. As a result, investors could expect T-DM1 to be safe and active as a 1st line treatment.

Another important readout is from the 3rd line phase II trial that served as the basis for the accelerated approval application which was declined by the FDA. Top line results were already presented last December, with an impressive response rate of 33%. At ESMO, the most important piece of data in the trial will be updated progression free survival (PFS) numbers. This will shed more light on T-DM1's prospects in the ongoing 2nd line phase III trial. At the last update, median PFS was ~7.3 months but this figure excluded many patients who were deriving benefit from T-DM1 and still had not progressed at the time. Therefore, updated numbers could be better than 7.3 months.

In summary, the ESMO conference should prove once again that T-DM1 is highly active and that fundamentally, T-DM1's prospects have not changed as a result of the recent rejection.

Another important read-out for Immunogen will be updated results for IMGN901 in Merkel Cell (MCC), a niche indication but also a potential fast route to market. To date, results in MCC were intriguing but somewhat ambiguous (discussed here under " Looking beyond T-DM1"). The market's expectations for this agent are low, so any positive data will be a pleasant surprise.

Disclosure: Long IMGN